InstallMate sets this variable to the total installation size of the currently active feature (in the active OptionTree control) and its selected subfeatures. This variable is used to display the feature's size in the installer's user interface. If the feature is not selected for installation, its size is set to 0.
You can refer to this variable as <TsuFeatureSize>. Do not change its value; it is set and updated automatically by InstallMate.